The present invention is in the field of patient examination tables. In general, the present invention is directed to a patient examination table capable of providing an angle of incline or decline about a horizontal axis for use in conducting disease diagnosis. In particular, the present invention provides a mobile examination tilt table capable of automatically providing accurate and reproducible angles of incline and decline, also known as Reverse Trendelenburg and Trendelenburg positions, for analysis of patient disease states such as syncope.
In various diagnostic procedures it is critical to be able to position the patient at various angles of incline and decline in order to assess various disease processes. In one such disease process, syncope, a patient will spontaneously faint due to difficulties in sustaining proper blood supply to the brain. To observe cardiac status at the time of fainting, it is necessary to place the patient in a nearly vertical position which will allow the fainting behavior to occur. In order to attempt to diagnose unexplained fainting, the patient is placed in a supine position on a tilt table, and the patient is inclined to a nearly upright position. This position is usually between 60xc2x0 degrees and 85xc2x0 degrees head-up from the horizontal. When the fainting episode occurs, it is vital to immediately and rapidly lower the patient into a horizontal or head-down position, or a Trendelenburg position in order to restore blood flow to the patient""s head and restore consciousness.
In carrying out this type of assessment of the patient""s condition, it is important to be able to position, and reposition, accurately the patient at various degrees of incline so syncopal episodes can be reproduced and observed repeatedly. It is equally important that the same patient be reproducibly positioned over time into the same position of incline to allow reassessment of the syncope episodes.
In general the prior art devices for conducting such tilt-table studies are fixed-in-place tables which require the user to determine the angle of incline or decline by using a mechanical indicator such as observing the bubble position in a bubble gauge inclinometer that is attached to the side of the movable table surface. This type of device relies upon the user to accurately observe the position of the angle and to be able to repeatably reproduce the angle. This presents a problem of incline accuracy and incline reproducibility when different operators are used and a span of time intervenes between two test periods. The present invention avoids these drawbacks of the prior art while providing additional xe2x80x9cone-buttonxe2x80x9d control of the tilt table movement to eliminate further the inaccuracy and irreproducibility which is presented by mechanical indicators such as bubble gauge inclinometers, the variation between different table operators and the variation of time intervening between test sessions.
The present invention provides accurate tilt or angle positioning of a patient and allows accurate reproduction of the selected angle of incline while permitting rapid repositioning of examination surface or assembly 12 into a Trendelenburg position of approximately negative 15xc2x0 or fifteen degrees below horizontal. The inventive combination further permits tilting a patient selectably at a fast or slow speed while automatically providing a ramping down of the motor speed as the patient approaches the desired angle.
A principal object of the present invention is to provide a tilt table for disease diagnosis having user selectable, accurate, and reproducible, automatic incline and decline positioning and repositioning of a patient. The table can also be mobile, in which case it provides accurate and reproducible repositioning from one diagnostic test to the next and from a first patient visit to a second patient visit and from a first table location to a second table location.
Another object of the present invention is to provide a portable tilt table having accurate and reproducible inclining and declining of a patient, using a variety of alternative methods, while accounting for the degree of slope present in the floor on which the invention is situated.
It is another object of the present invention to provide a portable tilt table which provides accurate and reproducible inclining and declining of a patient from visit to visit utilizing a number of equivalent devices even though the invention has been moved from one location to another between the patient visits.
Still another object of the present invention is to provide user selectable multiple speeds of movement of the tilt table between various angle of tilt positions.
Another object of the present invention is to recognize the remaining distance between a designed angle of incline and the present position of the tilt table to allow a reduction in the velocity of table movement to avoid sudden stopping of the table at the desired position and to avoid bumping and jerking movements of the patient during table incline and decline movement operations.
Yet another object of the tilt table of the present invention is to provide user programmable standard positions of incline and decline for use during patient disease diagnosis.
Yet another object of the present invention is to provide a device and method of accurately and precisely moving from a first table incline or decline position to a second position in a reproducible manner.
Another object of the present invention is to provide user selectable one-button emergency repositioning of a patient from an incline position to a decline position.
Still another object of the present invention is to provide user selectable one-button repositioning of a patient from an incline or decline position to a level of zero degree of incline or decline position.
Another object of the present invention is to provide user accurate and reproducible patient incline and decline positions by determining the table angle using an inclinometer communicating with a central processor to determine the table position of incline or decline.
Another object of the present invention is to provide the user the opportunity to preselect the position to which the bed will reposition when an emergency reposition button is selected by the operator.
Another object of the present invention is to provide user accurate and reproducible patient incline and decline positions by determining the amount of table movement toward an incline or decline angle using counter mechanism on the table tilt drive, the counter mechanism being in communication with a central processor to determine the table position along the path of incline or decline path of travel.
The foregoing and other objects are not meant in a limiting sense, and will be readily evident upon a study of the following specification and accompanying drawings comprising a part thereof. It is to be understood that all the above objects need not be present in every embodiment of the invention, rather various objects can be presented and satisfied in different embodiments. Other objects and advantages of this invention will become apparent from the following description taken in connection with the accompanying drawings, wherein is set forth by way of illustration and example, an embodiment of this invention.
These objects and more are provided by the present invention which comprises a table examination surface which is repositionable to various angles of incline or decline by use of a central processing unit (CPU) to determine when a selected angle of tilt is achieved. Repositioning of the examination surface can operate at various speeds by use of a variable speed motor to reposition the examination surface to any angle of incline or decline which is desired by the user. This is generally accomplished by method of the user selecting the desired examination surface angle of incline or decline and activating the variable speed drive. The variable speed drive is controlled by a computer processor which is in communication with a means for determining the position of the examination surface or examination assembly along a path of travel. When the exam surface approaches the desired angle of incline or decline the computer processor instructs the variable speed drive to reduce its velocity of movement of the examination surface to avoid sudden or jerky movement of the examination surface as it approaches the desired angle of incline or decline and to provide the patient with a more tolerable or comfortable cessation of travel.
The means for determining the position of the examination surface comprises an electronic form of inclinometer in one embodiment which provides a processor with a signal for use in positioning and repositioning the examination surface or table assembly of the tilt table. In another embodiment a shaft encoder on the the variable speed drive provides the means for determining the position of the examination surface. In yet another embodiment a combination of the inclinometer and the shaft encoder are used to position and reposition the examination surface or assembly of the tilt table.